3.
Has a problem been found?
 | ▶ Repair as necessary and then go to "Verification of Vehicle Repair" procedure. |
 | ▶ Go to "Power Circuit Inspection" procedure. |
Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check all connectors (and connections) for looseness, bending, corrosion, contamination, deterioration, and/or damage.
Has a problem been found?
| ▶ Repair as necessary and then go to "Verification of Vehicle Repair" procedure. |
| ▶ Go to "Power Circuit Inspection" procedure. |
Ignition switch "OFF"
Refer to "Shop Manual" and disconnect the lambda sensor unit connector.
Ignition Switch "ON"
Measure the voltage between heater power terminal of front lambda sensor unit harness connector and chassis ground.
Specification : B+
Is the measured value within specification?
| ▶ Go to "Control Circuit Inspection" procedure. |
| ▶ Inspect and repair open or short in circuit, and then go to "Verification of Vehicle Repair" procedure. |
Ignition switch "OFF"
Refer to "Shop Manual" and disconnect the lambda sensor unit connector.
Connect VMI to GDS and select oscilloscope.(2 Channel)
Channel A (+) : Heater control connector (On Lambda Sensor Connector)
Channel A (-) : Ground
Ignition Switch "ON"
Specification :
Average Voltage : Approx. 3.3V
Max. voltage : Approx 3.6V
Min Voltage : Approx. 0V
Duty (-) : Approx 2%
Fig.1) Lambda sensor heater control pull-up signal waveform.
Is the measured value within specification?
| ▶ Go to "Signal Circuit Inspection" procedure. |
| ▶ Inspect and repair open or short in circuit, and then go to "Verification of Vehicle Repair" procedure. |
Ignition switch "OFF"
Refer to "Shop Manual" and disconnect rear lambda sensor unit connector.
Connect VMI to GDS and set up the Oscilloscope.(4 Channel):
Channel A (+) : Nernst cell terminal (Rear Lambda Sensor Harness Connector)
Channel A (-) : Trim resistor terminal (Rear Lambda Sensor Harness Connector)
Channel B (+) : Pumping cell terminal (Rear Lambda Sensor Harness Connector)
Channel B (-) : Vertual ground terminal (Rear Lambda Sensor Harness Connector)
Ignition switch "ON"
Specification : Refer to figure below
Fig.1) Lambda sensor signal waveform when lambda sensor is active.
Is the measured value within specification?
| ▶ Go to "Component Inspection" procedure. |
| ▶ Inspect and repair open or short in circuit, and then go to "Verification of Vehicle Repair" procedure. |
